I have a black tag in my Cali 34. The HIN number is JCM340120178. The black tag says 34-12. The insurance company says the three numbers following JCM34 is your boat number that was made that year which coincides with the black tag. Mine being the 12th 34 ft Cali built in 1978. Still unsure what the 01 number following the 12 means. We purchased this boat as a project boat and all mechanical engines are working but had major rot from leaks in the windows. Looking forward to cruising this year.